On Mon, 22 Sep 2014 14:32:59 +0100
Markos Chandras <[email protected]> wrote:

> According to Documentation/trace/ftrace-design.txt, the selfpc
> should be the return address minus the mcount overhead (8 bytes).
> This brings static trace in line with the dynamic trace regarding
> the selfpc argument to the tracing function.
> 
> This also removes the magic number '8' with the proper
> MCOUNT_INSN_SIZE.

I could also update the generic code to handle delay slots.

-- Steve

> 
> Cc: Steven Rostedt <[email protected]>
> Cc: [email protected]
> Signed-off-by: Markos Chandras <[email protected]>
> ---
>  arch/mips/kernel/mcount.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S
> index 2f7c734771f4..3af48b7c7a47 100644
> --- a/arch/mips/kernel/mcount.S
> +++ b/arch/mips/kernel/mcount.S
> @@ -79,7 +79,7 @@ _mcount:
>       PTR_S   MCOUNT_RA_ADDRESS_REG, PT_R12(sp)
>  #endif
>  
> -     PTR_SUBU a0, ra, 8      /* arg1: self address */
> +     PTR_SUBU a0, ra, MCOUNT_INSN_SIZE /* arg1: self address */
>       PTR_LA   t1, _stext
>       sltu     t2, a0, t1     /* t2 = (a0 < _stext) */
>       PTR_LA   t1, _etext
> @@ -138,7 +138,7 @@ NESTED(_mcount, PT_SIZE, ra)
>  static_trace:
>       MCOUNT_SAVE_REGS
>  
> -     move    a0, ra          /* arg1: self return address */
> +     PTR_SUBU a0, ra, MCOUNT_INSN_SIZE       /* arg1: self address */
>       jalr    t2              /* (1) call *ftrace_trace_function */
>        move   a1, AT          /* arg2: parent's return address */
>  

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